This invention relates generally to radar systems, and more particularly to methods and systems that utilize Doppler prediction to set a height of fusing, for example, for a radar based weapon system.
A radar based weapon system is configured to fuse the weapon of the system at various low altitudes so that the weapon will have optimum impact. A dual antenna (i.e. one transmit antenna and one receive antenna) radar system installation within the weapon system that has sufficient separation between the two antennas is not practical for smaller weapon systems. One reason separation between the antennas is important is to reduce an antenna leakage signal that propagates between the two antennas. Sufficient antenna separation to measure elevations near or at ground level such that antenna leakage signals do not interfere with altitude measurements typically cannot be efficiently incorporated into smaller weapon systems. In these smaller weapon systems there is simply not enough room to adequately separate the two antennas.
In smaller weapons systems that incorporate two antennas, the two antenna apertures are necessarily located near one another other which significantly increases the antenna leakage signal. Therefore, with a dual antenna weapon system it is difficult to accurately measure certain low altitudes because the antenna leakage signals interfere with time coincident ground return signals.
A single antenna installation using a duplexer is even more difficult to implement in smaller weapons. The reason is that one antenna systems do not even exhibit some of the inherent antenna leakage isolation found in the dual antenna systems. Rather, signals similar to leakage signals are internal to the radar. As a result, it is also difficult for a one antenna radar sensor on a small weapon system to measure altitudes near or at ground level.